Subscriptions demo app

.gitignore

@@ -21,6 +21,10 @@ Gemfile.lock
 .ruby-version
 .DS_Store
 
+examples/subscriptions/log/*
+examples/subscriptions/tmp/*
+examples/subscriptions/storage/*
+
 ## Specific to RubyMotion:
 .dat*
 .repl_history

docs/subscriptions.md

@@ -69,7 +69,8 @@ class EntitiesSchema < GraphQL::Schema
     end
 
     def posts(ids:)
-      Post.where(id: ids)
+      records_by_id = Post.where(id: ids).index_by(&:id)
+      ids.map { |id| records_by_id[id] }
     end
 
     field :comments, [Comment, null: true] do
@@ -78,7 +79,8 @@ class EntitiesSchema < GraphQL::Schema
     end
 
     def comments(ids:)
-      Comment.where(id: ids)
+      records_by_id = Comment.where(id: ids).index_by(&:id)
+      ids.map { |id| records_by_id[id] }
     end
   end
 
@@ -185,7 +187,7 @@ class StitchedActionCableSubscriptions < GraphQL::Subscriptions::ActionCableSubs
   end
 end
 
-class SubscriptionSchema
+class SubscriptionSchema < GraphQL::Schema
   # switch the plugin on the subscriptions schema to use the patched class... 
   use StitchedActionCableSubscriptions
 end

examples/subscriptions/.gitattributes

@@ -0,0 +1,9 @@
+# See https://git-scm.com/docs/gitattributes for more about git attribute files.
+
+# Mark the database schema as having been generated.
+db/schema.rb linguist-generated
+
+# Mark any vendored files as having been vendored.
+vendor/* linguist-vendored
+config/credentials/*.yml.enc diff=rails_credentials
+config/credentials.yml.enc diff=rails_credentials

examples/subscriptions/.gitignore

@@ -0,0 +1,35 @@
+# See https://help.github.com/articles/ignoring-files for more about ignoring files.
+#
+# If you find yourself ignoring temporary files generated by your text editor
+# or operating system, you probably want to add a global ignore instead:
+#   git config --global core.excludesfile '~/.gitignore_global'
+
+# Ignore bundler config.
+/.bundle
+
+# Ignore all environment files (except templates).
+/.env*
+!/.env*.erb
+
+# Ignore all logfiles and tempfiles.
+/log/*
+/tmp/*
+!/log/.keep
+!/tmp/.keep
+
+# Ignore pidfiles, but keep the directory.
+/tmp/pids/*
+!/tmp/pids/
+!/tmp/pids/.keep
+
+# Ignore storage (uploaded files in development and any SQLite databases).
+/storage/*
+!/storage/.keep
+/tmp/storage/*
+!/tmp/storage/
+!/tmp/storage/.keep
+
+/public/assets
+
+# Ignore master key for decrypting credentials and more.
+/config/master.key

examples/subscriptions/Gemfile

@@ -0,0 +1,65 @@
+source "https://rubygems.org"
+
+ruby "3.1.1"
+
+# Bundle edge Rails instead: gem "rails", github: "rails/rails", branch: "main"
+gem "rails", "~> 7.1.3", ">= 7.1.3.4"
+
+# Use sqlite3 as the database for Active Record
+gem "sqlite3", "~> 1.4"
+
+# Use the Puma web server [https://github.com/puma/puma]
+gem "puma", ">= 5.0"
+
+# Use JavaScript with ESM import maps [https://github.com/rails/importmap-rails]
+gem "importmap-rails"
+
+# Hotwire's SPA-like page accelerator [https://turbo.hotwired.dev]
+gem "turbo-rails"
+
+# Hotwire's modest JavaScript framework [https://stimulus.hotwired.dev]
+gem "stimulus-rails"
+
+# Build JSON APIs with ease [https://github.com/rails/jbuilder]
+gem "jbuilder"
+
+# Use Redis adapter to run Action Cable in production
+gem "redis", ">= 4.0.1"
+
+# Use Kredis to get higher-level data types in Redis [https://github.com/rails/kredis]
+# gem "kredis"
+
+# Use Active Model has_secure_password [https://guides.rubyonrails.org/active_model_basics.html#securepassword]
+# gem "bcrypt", "~> 3.1.7"
+
+# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
+gem "tzinfo-data", platforms: %i[ mswin mswin64 mingw x64_mingw jruby ]
+
+# Reduces boot times through caching; required in config/boot.rb
+gem "bootsnap", require: false
+
+gem "graphql", "~> 2.3.0"
+
+group :development, :test do
+  # See https://guides.rubyonrails.org/debugging_rails_applications.html#debugging-with-the-debug-gem
+  gem "debug", platforms: %i[ mri mswin mswin64 mingw x64_mingw ]
+end
+
+group :development do
+  # Use console on exceptions pages [https://github.com/rails/web-console]
+  gem "web-console"
+
+  # Add speed badges [https://github.com/MiniProfiler/rack-mini-profiler]
+  # gem "rack-mini-profiler"
+
+  # Speed up commands on slow machines / big apps [https://github.com/rails/spring]
+  # gem "spring"
+
+  gem "error_highlight", ">= 0.4.0", platforms: [:ruby]
+end
+
+group :test do
+  # Use system testing [https://guides.rubyonrails.org/testing.html#system-testing]
+  gem "capybara"
+  gem "selenium-webdriver"
+end

examples/subscriptions/README.md

@@ -0,0 +1,38 @@
+# Subscriptions example
+
+This example demonstrates stitching subscriptions in a small Rails application. No database required, just bundle-install and try running it:
+
+```shell
+cd examples/subscriptions
+bundle install
+bin/rails s
+```
+
+Then visit the GraphiQL client running at [`http://localhost:3000`](http://localhost:3000) and try subscribing:
+
+```graphql
+subscription SubscribeToComments {
+  commentAddedToPost(postId: "1") {
+    post { 
+      id 
+      title
+      comments {
+        id
+        message
+      }
+    }
+    comment { 
+      id
+      message
+    }
+  }
+}
+```
+
+Upon running that subscription, you'll recieve an initial payload for the subscribe event that stitches post data from another schema. Now try triggering events by hitting this URL in another browser window:
+
+```
+http://localhost:3000/graphql/event
+```
+
+Each refresh of the above URL will add a comment and trigger a subscription event. Assuming you're subscribed, you should see comment activity appear in the GraphiQL output. Again, these update events are stitched to enrich the basic subscription payload with additional data from another schema.

examples/subscriptions/Rakefile

@@ -0,0 +1,6 @@
+# Add your own tasks in files placed in lib/tasks ending in .rake,
+# for example lib/tasks/capistrano.rake, and they will automatically be available to Rake.
+
+require_relative "config/application"
+
+Rails.application.load_tasks

examples/subscriptions/app/channels/graphql_channel.rb

@@ -0,0 +1,50 @@
+class GraphqlChannel < ActionCable::Channel::Base
+  def subscribed
+    @subscription_ids = []
+  end
+
+  def execute(data)
+    result = StitchedSchema.execute(
+      data["query"],
+      context: { channel: self },
+      variables: ensure_hash(data["variables"]),
+      operation_name: data["operationName"],
+    )
+
+    payload = {
+      result: result.to_h,
+      more: result.subscription?,
+    }
+
+    if result.context[:subscription_id]
+      @subscription_ids << result.context[:subscription_id]
+    end
+
+    transmit(payload)
+  end
+
+  def unsubscribed
+    @subscription_ids.each { |sid|
+      SubscriptionsSchema.subscriptions.delete_subscription(sid)
+    }
+  end
+
+  private
+
+  def ensure_hash(ambiguous_param)
+    case ambiguous_param
+    when String
+      if ambiguous_param.present?
+        ensure_hash(JSON.parse(ambiguous_param))
+      else
+        {}
+      end
+    when Hash, ActionController::Parameters
+      ambiguous_param
+    when nil
+      {}
+    else
+      raise ArgumentError, "Unexpected parameter: #{ambiguous_param}"
+    end
+  end
+end

examples/subscriptions/app/controllers/graphql_controller.rb

@@ -0,0 +1,44 @@
+class GraphqlController < ActionController::Base
+  skip_before_action :verify_authenticity_token
+  layout false
+
+  def client
+  end
+
+  def execute
+    result = StitchedSchema.execute(
+      params[:query],
+      variables: ensure_hash(params[:variables]), 
+      context: {}, 
+      operation_name: params[:operationName],
+    )
+
+    render json: result
+  end
+
+  COMMENTS = ["Great", "Meh", "Terrible"].freeze
+
+  def event
+    comment = Repository.add_comment("1", COMMENTS.sample)
+    render json: comment
+  end
+
+  private
+
+  def ensure_hash(ambiguous_param)
+    case ambiguous_param
+    when String
+      if ambiguous_param.present?
+        ensure_hash(JSON.parse(ambiguous_param))
+      else
+        {}
+      end
+    when Hash, ActionController::Parameters
+      ambiguous_param
+    when nil
+      {}
+    else
+      raise ArgumentError, "Unexpected parameter: #{ambiguous_param}"
+    end
+  end
+end

examples/subscriptions/app/graphql/entities_schema.rb

@@ -0,0 +1,42 @@
+class EntitiesSchema < GraphQL::Schema
+  class StitchingResolver < GraphQL::Schema::Directive
+    graphql_name "stitch"
+    locations FIELD_DEFINITION
+    argument :key, String, required: true
+    argument :arguments, String, required: false
+    repeatable true
+  end
+
+  class Comment < GraphQL::Schema::Object
+    field :id, ID, null: false
+    field :message, String, null: false
+  end
+
+  class Post < GraphQL::Schema::Object
+    field :id, ID, null: false
+    field :title, String, null: false
+    field :comments, [Comment, null: false], null: false
+  end
+
+  class QueryType < GraphQL::Schema::Object
+    field :posts, [Post, null: true] do
+      directive StitchingResolver, key: "id"
+      argument :ids, [ID], required: true
+    end
+
+    def posts(ids:)
+      ids.map { Repository.post(_1) }
+    end
+
+    field :comments, [Comment, null: true] do
+      directive StitchingResolver, key: "id"
+      argument :ids, [ID], required: true
+    end
+
+    def comments(ids:)
+      ids.map { Repository.comment(_1) }
+    end
+  end
+
+  query QueryType
+end

examples/subscriptions/app/graphql/stitched_schema.rb

@@ -0,0 +1,10 @@
+require_relative "../../../../lib/graphql/stitching"
+
+StitchedSchema = GraphQL::Stitching::Client.new(locations: {
+  entities: {
+    schema: EntitiesSchema,
+  },
+  subscriptions: {
+    schema: SubscriptionsSchema,
+  },
+})